Ground fault detection in AC systems using digital signal processing

A device, comprising:

• a first electrical path and a second electrical path configured to supply alternative current (AC) power to a load coupled to the device;
• a first current sense resistor configured to generate a first sense voltage corresponding to a first current flowing in the first electrical path;
• a second current sense resistor configured to generate a second sense voltage corresponding to a second current flowing in the second electrical path;
• a first analog-to-digital converter circuit configured to convert the first sense voltage to a first digital voltage;
• a second analog-to-digital converter circuit configured to convert the second sense voltage to a second digital voltage;
• and
• control circuitry configured to:
• process the first digital voltage and the second digital voltage to compute a measure of the first current and a measure of the second current, per cycle of the AC power, wherein the computed measure includes at least one of a peak current and a root mean square (RMS) current;
• determine a difference between the computed measure of the first current and the computed measure of the second current, per cycle of the AC power;
• and
• generate a control signal to interrupt current flow in the first and second electrical paths, in response to determining that the difference between the computed measure of the first current and the computed measure of the second current meets or exceeds a difference threshold for a given number of cycles of the AC power.

A method, comprising:

• sensing a first current flowing in a first wire and a second current flowing in a second wire, the first and second wires being configured to supply alternative current (AC) power to a load;
• generating first digital data corresponding to the first current, and second digital data corresponding to the second current;
• processing the first digital data and the second digital data to compute a measure of the first current and a measure of the second current, per cycle of the AC power, wherein the computed measure includes at least one of a peak current and a root mean square (RMS) current;
• determining a difference between the computed measure of the first current and the computed measure of the second current;
• and
• generating a control signal to interrupt current flow in the first and second wires, in response to determining that the difference between the computed measure of the first current and the computed measure of the second current meets or exceeds a difference threshold.